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We generalize Aztec diamond theorem (N. Elkies, G. Kuperberg, M. Larsen, and J. Propp, Alternating-sign matrices and domino tilings, Journal Algebraic Combinatoric, 1992) by showing that the numbers of tilings of a certain family of regions…

Combinatorics · Mathematics 2014-04-07 Tri Lai

A recent conjecture of Di Francesco states that the number of domino tilings of a certain family of regions on the square lattice is given by a product formula reminiscent of the one giving the number of alternating sign matrices. These…

Combinatorics · Mathematics 2021-04-20 Mihai Ciucu

We study decision problems on geometric tilings. First, we study a variant of the Domino problem where square tiles are replaced by geometric tiles of arbitrary shape. We show that this variant is undecidable regardless of the shapes,…

Discrete Mathematics · Computer Science 2025-11-13 Benjamin Hellouin de Menibus , Victor Lutfalla , Pascal Vanier

For various sets of tiles, we count the ways to tile an Aztec diamond of order $n$ using tiles from that set. The resulting function $f(n)$ often has interesting behavior when one looks at $n$ and $f(n)$ modulo powers of 2.

Combinatorics · Mathematics 2024-07-08 James Propp

Fairly shortly after the publication of the Aztec diamond theorem of Elkies, Kuperberg, Larsen and Propp in 1992, interest arose in finding the number of domino tilings of an Aztec diamond with an ``Aztec window,'' i.e.\ a hole in the shape…

Combinatorics · Mathematics 2025-08-11 Mihai Ciucu

We show how to count tilings of Aztec diamonds and hexagons with defects using determinants. In several cases these determinants can be evaluated in closed form. In particular, we obtain solutions to problems 1, 2, and 10 in James Propp's…

Combinatorics · Mathematics 2007-05-23 Harald Helfgott , Ira M. Gessel

In this paper we study colorings (or tilings) of the two-dimensional grid $\mathbb{Z}^2$. A coloring is said to be valid with respect to a set $P$ of $n\times m$ rectangular patterns if all $n\times m$ sub-patterns of the coloring are in…

Discrete Mathematics · Computer Science 2022-06-06 Jarkko Kari , Etienne Moutot

We use the subgraph replacement method to investigate new properties of the tilings of regions on the square lattice with diagonals drawn in. In particular, we show that the centrally symmetric tilings of a generalization of the Aztec…

Combinatorics · Mathematics 2019-05-20 Tri Lai

We describe computer algorithms that produce the complete set of isohedral tilings by n-omino or n-iamond tiles in which the tiles are fundamental domains and the tilings have 3-, 4-, or 6-fold rotational symmetry. The symmetry groups of…

Computational Geometry · Computer Science 2012-01-17 Hiroshi Fukuda , Chiaki Kanomata , Nobuaki Mutoh , Gisaku Nakamura , Doris Schattschneider

Motivated in part by Propp's intruded Aztec diamond regions, we consider hexagonal regions out of which two horizontal chains of triangular holes (called ferns) are removed, so that the chains are at the same height, and are attached to the…

Combinatorics · Mathematics 2019-05-20 Mihai Ciucu , Tri Lai

We introduce a family of domino tilings that includes tilings of the Aztec diamond and pyramid partitions as special cases. These tilings live in a strip of $\mathbb{Z}^2$ of the form $1 \leq x-y \leq 2\ell$ for some integer $\ell \geq 1$,…

Combinatorics · Mathematics 2017-09-11 Jérémie Bouttier , Guillaume Chapuy , Sylvie Corteel

We consider tilings of deficient rectangles by the set $\mathcal{T}_4$ of ribbon $L$-tetrominoes. A tiling exists iff the rectangle is a square of odd side. The missing cell is on the main NW--SE diagonal, in an odd position if the square…

Combinatorics · Mathematics 2017-02-10 Viorel Nitica

Inspired by Propp's intruded Aztec diamond regions, we consider halved hexagons in which two aligned arrays of triangular holes have been removed from their boundaries. Unlike the intruded Aztec diamonds (whose numbers of domino tilings…

Combinatorics · Mathematics 2019-02-12 Tri Lai

In this thesis, we consider domino tilings of three-dimensional regions, especially those of the form $\mathcal{D} \times [0,N]$. In particular, we investigate the connected components of the space of tilings of such regions by flips, the…

Combinatorics · Mathematics 2015-03-17 Pedro H. Milet

Di Francesco conjectured in 2021 that the number of domino tilings of a certain family of regions -- called Aztec triangles -- on the square lattice is given by a product formula reminiscent of the one giving the number of alternating sign…

Combinatorics · Mathematics 2025-08-07 Seok Hyun Byun , Mihai Ciucu

We consider tiling rectangles of size 4m x 4n by T-shaped tetrominoes. Each tile is assigned a weight that depends on its orientation and position on the lattice. For a particular choice of the weights, the generating function of tilings is…

Combinatorics · Mathematics 2007-08-30 Jesper Lykke Jacobsen

We consider tilings of quadriculated regions by dominoes and of triangulated regions by lozenges. We present an overview of results concerning tileability, enumeration and the structure of the space of tilings.

Combinatorics · Mathematics 2007-05-23 Nicolau C. Saldanha , Carlos Tomei

The periodic tiling conjecture asserts that if a region $\Sigma\subset \mathbb R^d$ tiles $\mathbb R^d$ by translations then it admits at least one fully periodic tiling. This conjecture is known to hold in $\mathbb R$, and recently it was…

Combinatorics · Mathematics 2024-09-26 Jaume de Dios Pont , Jan Grebík , Rachel Greenfeld , Jose Madrid

Given a tiling of a 2D grid with several types of tiles, we can count for every row and column how many tiles of each type it intersects. These numbers are called the_projections_. We are interested in the problem of reconstructing a tiling…

Computational Complexity · Computer Science 2009-09-25 Marek Chrobak , Peter Couperus , Christoph Durr , Gerhard Woeginger

Given a graph, when can we orient the edges to satisfy local constraints at the vertices, where each vertex specifies which local orientations of its incident edges are allowed? This family of graph orientation problems is a special kind of…

Computational Complexity · Computer Science 2026-03-05 MIT Hardness Group , Zachary Abel , Erik D. Demaine , Jenny Diomidova , Jeffery Li , Zixiang Zhou